JPH0673971B2 - Electrophotographic printer - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an electrophotographic printer that launches an electrophotographic process during data conversion.

(Prior Art) In such an electrophotographic printer, conventionally, since it takes time to start up the image forming process unit (photosensitive drum, charger, etc.), it is started during data conversion, and after conversion is completed. , I was trying to print immediately.

(Problems to be solved by the invention) In a page printer capable of graphic drawing,
When drawing graphics, the host (data processing device)
The image data is received, the received data is converted into print data for one page, and printing is performed. For printing, an electrophotographic method using laser exposure is used.

In such a page printer, when the above paper advance control is performed, in the electrophotographic printer, laser exposure cannot be performed unless the drum is in a constant speed state, so the image forming process unit (drum, charger, etc.) , It is always in operation even during signal conversion.

However, in a page printer capable of graphic drawing, the data conversion time may be extremely long (for example, several minutes to several tens of minutes for one page of data). However, the drum, rollers, etc. of the image forming process section
Since the rotation continues unnecessarily during data conversion, the reduction in life becomes a problem.

In order to solve this point, the present applicant proposes to automatically stop the image forming process unit and put the printer in a standby state when the conversion time exceeds a predetermined time.

An object of the present invention is to provide an electrophotographic printer capable of graphic drawing, which is capable of preventing the wasteful reduction of the life of the image forming process unit in graphic drawing and improving the throughput by the paper advance control in printing. That is.

(Means for Solving Problems) An electrophotographic printer according to the present invention includes a communication unit that receives a code of information to be printed, a conversion unit that converts the code received by the communication unit into image data, and a conversion unit. Printing means for performing printing by an electrophotographic process based on the image data converted by the conversion means; startup means for activating each part of the electronic process to start the printing means during conversion by the conversion means; When the conversion time exceeds a predetermined time, the clocking means that outputs a signal, and when the above-mentioned clocking means outputs a signal, in the next print, the startup by the startup means during data conversion is prohibited and Print control means for starting the printing means after the conversion is completed.

(Operation) If the time required for converting the received data exceeds the predetermined time,
In the next printing, the activation of the printing means during the data conversion is prohibited, and the printing means is activated after the data conversion is completed.

Embodiments Embodiments of the present invention will be described below in the following order with reference to the accompanying drawings.

Configuration of electrophotographic printer b. Flow of bitmap control c. Flow of interface control d. Flow of electrophotographic control e. Flow of print head control The embodiment part particularly related to the present invention is described in section (a). other,
The processing of steps # 114 to 119 (FIG. 9) in section (b),
These are the conditions for measuring the time in steps # 207 to 211 (FIG. 1) and feeding the next copy in step # 214 (FIG. 1) in section (c).

(A) Configuration of Electrophotographic Printer FIG. 2 is a configuration of a processing system by a printer system 10 capable of graphic drawing which is an embodiment of the present invention.

Data from the general-purpose data processing device 1 is stored in the file buffer 2 and then output to the printer system 10 in order to improve the throughput of the data processing device 1.

The printer system 10 comprises a bitmap data processing device 3, a print engine 4 using an electrophotographic process and a laser, and an auxiliary device such as an external paper feeding unit 5 and a sorter 6.

FIG. 3 is a schematic block diagram of the control of the printer system 10.

The bitmap data processing device 3 includes a bitmap control unit 30 (see FIG. 4), a bitmap BM-RAM 32, a bitmap writing unit 31 (see FIG. 5) for drawing on the BM-RAM 32, and It consists of the font part 33. The connection with the print engine 4 is made by a bus B3 for control data (number of sheets, accessory control, etc.) and a bus B4 for image data.

The print engine 4 is mainly composed of three controllers. First, the interface control unit 40 processes the control data from the bitmap control unit 30, controls the display panel, and controls the timing of the entire printer 4 through the internal bus B5. Electrophotographic control unit 41 (see FIG. 7)
Controls the electrophotographic process unit 45 according to the data sent from the interface control unit 40 through the internal bus B5.

The print head control unit 42 (see FIG. 8) receives the image data sent via the bitmap writing unit 31 and the internal bus B4 from the interface control unit via the internal bus B5.
Print head unit 43 according to the information sent from 40
(See FIG. 8) The semiconductor laser 431 is controlled by the semiconductor laser 431 (see FIG. 8) and the polygon motor 432 is controlled.
Control the rotation of.

The external paper feeding unit 5 and the sorter 6 are also controlled by the interface controller 40 via the internal bus B5.

FIG. 4 is a block diagram of the bitmap control unit 30.
The bitmap control unit 30 is composed of several blocks connected by an internal bus B301. The BM-CPU 301 is a central control unit of the bitmap type data processing device 3, communicates with the data processing device 1 through the data processing device interface 308, converts print data, and outputs a bitmap writing interface. The bitmap writing unit 31 is controlled via 306, and the print engine 4 is controlled via the print engine interface 307. The SYS-ROM 302 stores the program of the BM-CPU 301. The SYS-RAM 303 is a working storage area of the BM-CPU 301, and is used for storing the stack and basic flag.

The R-buffer 304 is a buffer for communication with the data processing device 1, and is intended for asynchronous communication between the processing program of the BM-CPU 301 and the data processing device 1.

The P-RAM 305 stores the attributes of each font loaded by the bitmap writing unit 31 from the font unit 33 and the data from the data processing device 1 as an intermediate code converted from the font attributes for printing.

The print engine interface 307 is an interface with the print engine 4, and exchanges job information such as the number of prints and job control commands such as print commands with the interface of the print engine 4 through the bus B3.

FIG. 5 shows a detailed block diagram of the bitmap writing unit 31. The functions of the bitmap writing unit 31 are roughly classified into BM-RAM32
To a print engine 4 and a function to output the data of the BM-RAM 32 to the print engine 4 at the time of printing.

The function of drawing on the BM-RAM 32 is further divided into two, and is composed of line and circle drawing performed by the graphic image writing unit 316 and font drawing performed by the font image writing unit 311. Both are bitmap control units 30 through the bitmap control unit interface 317.
Although it is a logic unit that operates with the intermediate code sent from, most of the processing of the graphic image writing unit 316 is
While the parameters in the intermediate code are analyzed and drawn in the BM-RAM 32, most of the processing of the font image writing unit 311 is read from the font unit 33 through the font unit interface 314 according to the data in the intermediate code. Draw the font image in BM-RAM32.

On the other hand, the function of outputting data at the time of printing is performed by the print head controller interface 315. That is, when the print start code sent from the bitmap control unit 30 via the interface 317 is received,
The data of the BM-RAM 32 is output to the print head control unit 40 according to the synchronizing signal sent from the print head control unit 42 (see FIG. 8) of the print engine 4 through the bus B4.

FIG. 6 is a detailed block diagram of the interface control unit 40 of the print engine 4. Interface control unit
40 is IFC-using a one-chip microcomputer
The CPU 400 is mainly configured, and an external ROM 407, RAM 408 and an interface 409 with the bitmap control unit 30 are connected via a bus B401 extended by an interface 404 of the IFC-CPU 400. The external ROM 407 is
It can be replaced by a socket, and a standard program is stored in the mask ROM 403 inside the IFC-CPU 400, while a different program is stored in the external ROM 407 depending on the destination.

The IFC-CPU 400 includes a CPU 401, RAM 402, ROM 403, a serial input / output unit (SIO) 405 for serial communication, and a parallel input / output unit (PIO) 406. The SIO 405 is a bus for controlling the electrophotographic control unit 41 and the print head control unit 42.
Control B5. The PIO 406 is used to control the display panel 44.

FIG. 7 is a detailed block diagram of the electrophotographic control unit 41.
The electrophotographic control unit 41 is a one-chip type similar to the IFC-CPU400.
It is controlled by the microcomputer MC-CPU410. CPU411
A RAM 413 and a ROM 414 are connected to. Unlike the interface control unit 40, only the standard program is not expanded. The serial input / output unit (SIO) 412 communicates with the interface control unit 40 via the bus B5. The parallel input / output unit (PIO) 415 is used for input / output of process control.

FIG. 8 is a detailed block diagram of the printhead controller 42. The print head control unit 42 controls the rotation of the polygon motor 432 of the print head unit 43 in accordance with the data sent from the interface control unit 40 via the bus B5, and the bitmap type data processing device 3 to the bus B4. The light emission of the semiconductor laser 431 is controlled in synchronization with the signal from the scanning detector (SOS) 433 of the laser scan by the image data sent through.

The print head control unit 42 is mainly composed of the one-chip microcomputer PHC-CPU 420 like the electrophotographic control unit 41, and the serial input / output unit (SIO) 422 communicates with the interface control unit 40. Bus B5 is connected. The parallel input / output unit (PIO) 425 has a semiconductor laser according to the image data from the polygon motor driving unit 427 that drives the polygon motor 432, the scanning detector (SOS) 433, and the bitmap data processing device 3. A printhead control circuit 426 is connected to control the emission of light.

The image data sent via the bus B4 is in parallel format, and the printhead control circuit 426 mainly performs parallel-serial conversion for causing the semiconductor laser 431 to sequentially emit light according to the image data. It also generates a timing signal for synchronizing the image data transfer to the print head control unit interface 315.

(B) Flowchart of Bitmap Control The operation of this system will now be described with reference to the flowchart.

9 to 11 are flowcharts showing the processing of the bitmap control unit 30. In FIG. 9, when the power is turned on (step # 100), internal initialization is performed (step # 101), and the print image area BM-RAM3.
2, P-RAM 305 that stores the value obtained by converting the data received from the data processing device 1 into an intermediate code, JOB that indicates the printing operation
The ACT flag and the BM-WRITE flag indicating the write state of the BM-RAM 32 are reset (step # 102), and the font attributes are read from the font section 33 (step # 10).
3). As described in section (d), the electrophotographic control unit 41 controls the temperature of the fixing unit and starts the cooling fan (step # 301, standby mode 1).

Next, the reception data processing loop is entered. The first processing is processing of received data. First, it is checked whether or not there is space in the P-RAM 305 (step # 104). If there is space, the 11th
By the interrupt processing routine shown in the figure, the R-buffer 304
The received data from the data processing device 1 stored in the data processing device 1 is taken out (step # 105, step # 106), and the processing corresponding to the code (see FIG. 10) is performed (step # 10).
7).

FIG. 10 shows the contents of the received data processing (step # 107). Received data includes print engine related code,
JOB control code, format control code and print code 4
There are types. Of these, the print engine related code is output to the interface control unit 40 (step #
151,152). There are two JOB control codes, a PAGE EJECT code used to separate pages and a JOB START code used to separate jobs (one page group). The JOB control code is stored in the P-RAM 305 as a corresponding flag (step # 153 to step # 156). In the case of the format control code (step # 157), the write address of the next character to the BM-RAM32 is changed (step # 158). Other received data is regarded as a character code, and the bitmap writing unit
Convert to intermediate code and write to P-RAM305 for output to 31. The format of the intermediate code is font address (step # 159), write address to BM-RAM32 (step # 16).
0) and write mode (step # 161). After this, depending on the font size etc., the BM of the next font
-Change the write address to RAM32 (Step # 16)
2). However, it does not change when drawing lines or circles.

Returning to FIG. 9, the intermediate code written in P-RAM305 is BM.
-RAM32 not in use for printing (step # 10
If NO in step 8) and if multi-printing is not in progress (NO in step # 109), the data is output to the bitmap writing unit 31 (step # 116). However, while the previous character is being drawn (YES in step # 110), the next drawing cannot be performed. If the first data is written (BM-WRITE flag = 0) (steps # 111 and 112), the BM-WRITE flag is set to 1 (step # 113), and the print engine 4 is prepared in advance for paper feeding and the like. The paper first-out command PFCMD is output to the interface control unit 40 (step # 114). As a result, when the print preparation of the bitmap type data processing device 3 is completed (steps # 305 to # 3).
(Refer to 11), the laser exposure to the photoconductor becomes possible immediately, and the throughput is improved by taking charge of the paper feeding time.

Output from the P-RAM 305 to the bitmap writing unit 31 is sequentially performed as long as there is intermediate code data.
When the ECT code is detected (YES in step # 115), since the signal conversion for one page is completed, the printing operation is started.
First, the JOBACT flag is set to prohibit writing to BM-RAM32, and updating of BM-RAM32 is prohibited (step # 11).
7) The print head controller interface 315 is set to the printable state (step # 118), and the print command PRNCMD is output to the interface controller 40 (step # 119). As a result, in the printhead controller interface 315, the BM-RAM32 is synchronized with the pulse sent from the control circuit 426 of the printhead controller 42.
The data of is output through the bus B4.

During the printing operation, the operation check of the print head control unit interface 315 gives YES at step # 108. Therefore, the received data is converted for the next printing and P-
Only the process of outputting to RAM 305 (steps # 104 to 107) is performed.

When printing is completed, the JOBACT flag is still set, so the process proceeds from step # 109 to step # 120, and the exposure end command EXPEND from the interface controller 40 is sent.
(See step # 413) Wait. This is because the interface controller 40 controls the number of sheets in the case of multi-printing. If the JOBEND flag, which is a parameter of this command, is set, the JOBACT flag is reset and the BM-RAM32 is cleared (step # 12
2) Start preparing to print the next page. If the multi-print is not completed, the next print is started with the same BM-RAM data (step # 118 and thereafter).

FIG. 11 shows a flow when there is an interrupt of data transmission from the data processing device 1. When there is an interrupt, the data is read from the data processing device 1 (step # 181) and written in the R-buffer 304 of the bitmap control unit 30 (step # 182). Then return.

(C) Interface Control Flow FIG. 1 is a processing flow of the interface control unit 40. In the interface control unit 40, after the power is turned on and after the internal initialization is performed (step # 201), the electrophotographic control unit 4
1, a start signal is sent to the print head controller 42, the sorter 6 and the external paper feeding unit 5 through the bus B5 to initialize the entire system of the print engine 4 (step # 202). Then, PFENB that indicates permission to feed paper first
The initial value 1 of the flag is set (step # 203), and the following processing loop is entered.

In the processing loop, first, a standby command (PFCMD, see step # 114) from the bitmap control unit 30 is waited for (step # 204). When the first-out command is received and if the first-out command is permitted (PFENB = 1) (step # 205), a supply request signal (FEEDRE) is sent to the electrophotographic controller 41 through the bus B5.
Q) is output (step # 206). As a result, the electrophotographic control unit 41 starts the activation of the electrophotographic process unit 45 for feeding and printing. However, the paper is in a standby state (“first-out” state) at a predetermined position. However, when the external paper feeding unit 5 is designated, the electrophotographic control unit 41 only activates the electrophotographic process unit 45, and paper feeding is performed by the external paper feeding unit 5. The standby position of the paper is the same.

Then, the interface control unit 40 waits for a print command (PRNCMD) (step # 211), and at the same time, sets a temporary value 1 to the NPFENB flag indicating permission for advance print of the next print and starts a predetermined timer T (step S21). # 207). This timer T has two functions. First, one is the BM-RAM in the bitmap control unit 30.
If drawing to 32 takes a long time, the electrophotographic process section 45
In order to prevent the life of the photosensitive drum and each part of the electrophotographic process from being shortened, the STANDBY signal is sent (step # 209) at the end of the timer T (step # 209), and the print engine 4 is in a stopped state (standby mode 2). As a result, the reduction in the life of the image forming process unit is greatly improved. Once the standby mode 2 is entered, the next paper feeding and activation of the image forming process will be performed after the conversion of the received data into the intermediate code is completed. Another function indicates the next advance permission
By resetting NPFENB (step # 210),
It is to prohibit the advance of the paper at the time of the next printing. This is because the same type of information is usually printed frequently in one job (for example, graphic data is continuously printed), so this is predicted, and there is an effect of preventing a reduction in life. With this method, the throughput will decrease, but even if the paper feed-out is prohibited once, NPFENB is set if the print command PRNCMD is input before the timer T ends at the next printing. Since it is left as it is, it will be put out first in the next print. (Usually, the paper is "first out" before the end of data conversion and is kept in standby by the timing roller, so the throughput does not decrease.) Through the above two functions, it is possible to improve the throughput and at the same time prevent the wasteful decrease of the service life. Become.

In the interface control unit 40, the print command PRNC
When the MD is received (step # 211) and the paper is not fed first (PFENB = 0) (step # 212), the paper feed request signal (FEEDREQ) is output (step # 213), and PFENB of the next print is output. Update the flags (step # 2
14). That is, when the print data is generated, the paper feeding is executed (step # 304, step # 321, step # 30).
7-311), and carry the paper to the specified position.

Further, the STANDBY signal is turned off (step # 215), that is, the standby mode 2 is released, and the MCRDY signal indicating that the image forming process unit of the electrophotographic control unit 41 is stable is sent from the electrophotographic process unit 45. Come (step # 216),
The EXPENB signal indicating exposure permission is output (step # 21).
7). As a result, the actual exposure is performed by the print head controller 42.
Done in. When the exposure is completed, the print head controller 42 outputs the EXPEND signal (see step # 413). When this is detected by the interface control unit 40 (step # 218), E is sent to the bitmap control unit 30.
Output the XPEND command (step # 219), then PFCM again
D waits.

The standby mode 2 in this embodiment is different from the auto shut of a normal printer or electrophotographic copying machine in the following points.

The paper is put on standby by the timing roller.

The process of converting the received code into print is being performed.

FIG. 12 shows the operation timing of the image forming process unit in this embodiment in comparison with the conventional example. As shown in the figure,
When it takes a long time to convert the data (timer T times up), the main motor is stopped and the standby mode 2 is set. At this time, the main charger and the phenomenon bias voltage are sequentially stopped before the main motor is stopped.
In addition to the above control, the interface control unit 40 controls communication within the print engine 4, and the bus B5
Through the exchange of data with each control unit through, the relay function for communication between each control unit is also provided. Since it is not directly related to the present invention, detailed description will be omitted.

The effect of the advance timing control in the present embodiment has been described with respect to the conversion time from the received data to the intermediate code, and the drawing time in the bitmap writing unit 31 is long. Even if it is short, the same effect can be obtained when the transmission time from the data processing device 1 or the file buffer 2 is long.

(D) Flow of electrophotographic control FIG. 13 is an operation flow of the electrophotographic control unit 41. In the electrophotographic control unit 41, after the power is turned on (Step # 300), the internal initialization is performed (Step # 301), and the activation signal (see Step # 202) from the interface control unit 40 waits for input (Step # 302). ).

When the activation signal is detected (step # 302), the command PECMD (see step # 114) is received from the interface control unit 40, and the FEEDREQ signal is output (step # 304), the standby mode is kept in the standby mode (step # 304). 303)
Becomes In the standby mode 1, the main motor and the drum are not rotated, and only the temperature control of the fixing unit and the turning on of the cooling fan are performed.

When the FEEDREQ signal is received (step # 304). The image forming process section is started for printing (main motor is turned on, etc.) (step # 305), the MCRDY signal indicating that preparation is completed is output to the interface control section 40 (step # 306), and the paper is fed. Start (step # 307).

A predetermined timer T ₁ is set at the same time as the feeding is started (step # 308), and when the timer T ₁ ends and the paper approaches the predetermined standby position (step # 309), the print head controller 42 is controlled. On the other hand, the PRDY signal indicating that the preparation of the paper is completed is output (step # 310), and the paper is stopped (step # 311).

Usually, the print command (PRNCMD) is immediately output from the bitmap control unit 30 (see step # 119), and then the paper restart signal TRON signal is output from the print head control unit 42 (see step # 411), By detecting this signal in the electrophotographic control section 41 (step # 318), the paper is restarted from the position of the timing roller (step # 319), and the image on the photosensitive drum is transferred to the paper. After that, the electrophotographic control unit 41 further sets a predetermined timer T ₂ (step # 320) and waits for the next FEEDREQ signal (step # 320).
321), when a signal is input, the next paper feeding is started (step # 306). If no signal is input by the end of timer T ₂ (YES in step # 322), standby mode 1
Return to (step # 303).

If the TRON signal is not output from the print head control unit 42 because the processing time in the bitmap control unit 30 or the transmission time from the data processing device 1 is long (the bitmap control unit 30 prints to the interface control unit 40). If no command is output), the interface controller 40 outputs a STANDBY signal (step # 209).
reference). When the electrophotographic controller 41 detects this signal (step # 312), it sends an MCR to the interface controller 40.
The DY signal is turned off (step # 313) and the standby mode 2 is entered (step # 314). In this mode, all processes including the main motor are stopped, and the paper is in the waiting state at the waiting position. This is to prevent the life of the printer from being unnecessarily shortened. Then the bitmap controller
When the signal conversion processing in 30 is completed and the STANDBY signal is turned off in the interface control unit 40, the electrophotographic control unit 41
Then, this is detected (step # 315), the image forming process section is restarted (step # 316), and the MCRDY signal is output again to the interface control section 40 (step # 31).
7).

(E) Print Head Control Flow FIG. 14 shows a processing flow in the print head controller 42. In the print head control unit 42, after the power is turned on (step # 400), internal initialization is performed (step # 401), and similarly to the electrophotographic control unit 41, a start signal from the interface control unit 40 (see step # 202). After detecting (step # 402), the processing loop is entered.

In the processing loop, first, the print start waits.
There are two conditions for starting printing. One is the laser exposure permission signal EXPE from the interface controller 40.
NB (step # 406) and interface control unit 4
It is output from 0 (see step # 217). The other is
This is a PM LOCK signal indicating that the polygon motor 432 has reached a predetermined rotation speed. The polygon motor 432 is controlled at the same timing as the main motor (step # 403),
While the electrophotographic control unit 41 is in the standby mode 1 or the standby mode 2 and the main motor is stopped, in order to extend the life of the polygon motor 432, the polygon motor 432 rotates at half the normal rotational speed (half speed). In step # 405), when printing is started and the main motor is turned on, the full speed state (step # 404) is reached, which is the normal rotation speed. Then, a PMLOCK signal indicating that the rotation speed is stable in the full speed state is output from the polygon motor drive unit 427. If the two conditions are satisfied (YES in step # 406 and step # 407), a start signal is sent to the print head control circuit 426 to start exposure (step # 408). As a result, the print head control circuit 426 sequentially requests the image data from the bitmap writing unit 31 and controls the light emission of the laser diode 431 according to the received data.

Further, the print head controller 42 starts two predetermined timers T ₁ and T ₂ at the same time when the exposure is started (step # 409). T ₁ is a fixed timer that does not depend on the paper size and restarts the paper at the standby position to control the registration timing. Timer T ₁
When step S410 ends (step # 410), a TRON signal is output to the electrophotographic controller 41 (step # 411).

Further, T ₂ is for synchronizing with the bitmap control unit 30, and is variable depending on the paper size. Timer T ₂
Ends (step # 412), the EXPEND signal is output to the interface controller 40 (step # 41).
3).

(Effect of the Invention) Normally, since the printing means is started during the conversion of data, printing can be executed immediately after the completion of data conversion, and the throughput is improved. If the data conversion time becomes longer, the next print will
Since the printing means is started after the data conversion is completed, the electrophotographic process unit does not continue to operate unnecessarily for a long time during the data conversion. This focuses on the fact that the same type of information is usually printed in a single job.
For example, after printing graphic data that requires time for data conversion, there is a high possibility that graphic data will be handled in the next print in the same job, and again it takes time for data conversion.

[Brief description of drawings]

FIG. 1 is a flowchart of the operation of the interface controller. FIG. 2 is a system configuration diagram of the electrophotographic printer according to the embodiment of the present invention. FIG. 3 is a block diagram of a bitmap type data processing device and a print engine. FIG. 4 is a block diagram of the bitmap control unit. FIG. 5 is a block diagram of the bitmap writing unit. FIG. 6 is a block diagram of the interface controller. FIG. 7 is a block diagram of the electrophotographic control section. FIG. 8 is a block diagram of the print head control unit and the print head unit. FIG. 9 is a flowchart of the operation of the bitmap control unit. FIG. 10 is a flowchart of the operation of received data processing. FIG. 11 is a flowchart of the operation of reception interrupt. FIG. 12 is a timing chart of the operation of the image forming process unit. FIG. 13 is a flowchart of the operation of the electrophotographic control unit. FIG. 14 is a flowchart of the operation of the print head controller. 1 ... Data processing device, 3 ... Bitmap type data processing device, 4 ... Print engine, 10 ... Printer system, 30 ... Bitmap control unit, 31 ... Bitmap writing unit, 40 ... Interface Control unit, 41 …… Electrophotographic control unit, 43 …… Print head unit.

Claims (1)

[Claims] 1. A communication means for receiving a code of information to be printed, a conversion means for converting the code received by the communication means into image data, and an electrophotographic process for printing based on the image data converted by the conversion means. A printing means for executing the above, a startup means for activating each electronic process unit to start the printing means during conversion by the conversion means, and a signal output when the conversion time of the conversion means exceeds a predetermined time. And a print control means for prohibiting the start-up during the data conversion by the start-up means and starting the print means after the data conversion is completed when the above-mentioned time-measurement means outputs a signal. An electrophotographic printer characterized by that.